#all{
    padding-top:60px;width:600px;margin:0 auto;}
#top{
    border: 1px solid red;
    height: 60px;
    background: aqua;
}
#top img:nth-child(1){
    display: block;
    height: 40px;
    /*logo的定位一般都是绝对定位。*/
    position: absolute;
    margin: 10px 0 0 460px;
}
#top img:nth-child(2){
    display: none;
    height: 40px;
    position: absolute;
    margin: 10px 0 0 460px;
}
#top div{
    border: 1px solid gray;
    width: 100px;
    height: 45px;
    text-align: center;
    background: aquamarine;
}
/*第一个div的位置调整*/
#top div:nth-child(2){
    margin:15px 0 0 20px;
}
/*第二个div的位置调整*/
#top div:nth-child(3){
    margin:-47px 0 0 130px;
}
#ipt1,#ipt2{cursor: pointer;color: #FFFFFF}
#mid{
    border: 1px solid green;
    height: 200px;
    background: cornflowerblue;
}
#mid div:nth-child(1){
    margin:0 30px 0 0;
    display: block;
}
#mid div:nth-child(2){
    display:none;
}
#mid div:nth-child(3){
    margin:30px 0 0 0;
    border:1px solid darkgray;
    height: 50px;
}
#btn1{
    margin-left: 20px;
}
#mid #btn2{
    height: 25px;
    margin-top: 10px;
    margin-left: 380px;
    padding:0 0 0 16px;
    background:url("../images/1.png")no-repeat;
}
#bot{border: 1px solid blue;
    height: 180px;
    background: #ff7f50;
}
#bot #div3,#div4{
    display: none;
}